It is well known that electronic equipment tends to emit electromagnetic energy during operation. It is also well known that effective operation of electronic equipment can be jeopardized by ambient electromagnetic energy emitted by other electronic devices positioned nearby. This is commonly called electromagnetic interference. In both civilian and military applications, a set of electromagnetic interference criteria have been developed and specified to define electromagnetic emission restraints and acceptable levels of electromagnetic emissions susceptibility.
Historically, continued electromagnetic interference difficulties have caused the adoption of system design practices that dictate the use of shielded cabling between system components to insure minimal emission of electromagnetic energy and interference with other proximately located system components during data transfer operations. Use of this method of electromagnetic interference reduction requires significant amounts of inter-system component cabling installed at considerable cost. Inter-system component cabling also occupies valuable space in and adds unnecessary weight to the system. This can pose significant problem with system component placement in space and weight sensitive applications, for example, military aircraft.
Advances in communications technology now provide for reliable wireless signal transmission and reception at electromagnetic signal field strengths significantly below the established electromagnetic interference criteria. Thus, data transmission between system components may be accomplished without using expensive inter-system component cabling. However, these advances in communications technology have not completely solved the electromagnetic field and interference problems associated with system component communications.
As is well known, the electromagnetic field emitted by wireless transceivers or other individual system components within the confined system area tends to bounce and reflect off nearby structures having electromagnetic wave reflective characteristics creating a contained electromagnetic field. The combination of direct and reflected electromagnetic energy within the contained electromagnetic field creates standing electromagnetic waves that exhibit widely differing field strengths throughout the confined system area. Efficient and effective wireless data transmission to individual system components positioned in areas of low electromagnetic field strength (dead zones) is therefore difficult, if not impossible. Furthermore, movement of reflective structures within the confined system area changes the reflected energy paths and alters the standing wave pattern and locations where dead zones are encountered. Thus, it is not feasible to permanently position individual system components within the confined system area as it is impossible to adequately predict and insure necessary electromagnetic field strengths at a given location within a contained electromagnetic field.
Accordingly, there is a need for a less expensive and more predictable method for transmitting data by electromagnetic radiation within an enclosed area defining a contained electromagnetic field.